Oceanic Alpha 8 info

[AquaNSun]

Hi,

I would like to know some info for my Alpha 7 and 8 second stage.

1. Nylon lock nut, part# 4336, what size thread is this?
2. Orifice O-Ring, part# 2.010, how do you read the size from it's part number?
3. Coupling O-Ring, part# 3.906, how do you read the size from it's part number?

Thanks and greatly appreciated.

 

[redacted]

For o-ring sizes, just put a dash in front of the last three digits. So you need a -010 and a -906 for your Alpha7/8. Take the nyloc nut down to your local hardware store to determine thread size.

 

[AquaNSun]

Awesome! I was looking at O-ring chart at oringusa.com and was wondering....

1. For Orifice and inlet coupling O-rings, would EPDM, 70-duro, be the appropriate choice for non-nitrox static applications in 2nd stages? The 70-duro, soft kind, was mentioned by oringusa as the standard and should be used whenever possible as the 90-duro might be too stiff? Would like to hear your experience.

2. It seems that most O-rings are classified under AS568 category, if that matters?

The nylon locknut is very small and I'll need to find another specialty store to confirm it's thread size. Been to regular hardware stores, like home depot, and all of them don't carry such small size. The closest size guessed so far is 4-40 thread. I read somewhere 5-40 thread so it's getting closed.

 

[fppf]

The only reason for you asking these questions is your trying to service your reg without access to factory kits. I would not recommend doing this. There are parts in the factory service kits you can not get anywhere else.

Oceanic does not support user regulator servicing.

 

[AquaNSun]

IMHO I think there are 2 groups of people.

1st group: Divers trying to service their own regs to save money without knowing what's going on, no ideas of working mechanisms of parts and their functions - That is a NO NO and dangerous thing to do. DON'T do it.

2nd group: Divers with curious minds trying to experiment, understand, learn the inside out of their regs, read manuals, books, threads, educate themselves and get satisfactions from making their regs work!

This kind of satisfaction is beyond what I can describe here. The reasons Im doing this is because I want to know how my regs work, Im very interested and curious to understand how each part comes together and works as a unit. I can just read books but I love to take things apart, touch them, look at them up close, research forums, and make my brain thinks. This hands on experience is invaluable. I believe that I'll become a safer diver because I can check my own regs, trouble shoot problems and know when to stop.

The reason Im experimenting with Alpha 7 is because that's the simplest 2nd stage, that I know, and very easy to understant its working parts. It's true that parts like poppet, orifice, and lever arms can only come from manufacturers, but O-rings, Nylon locks, and washers are common items that can be found outside. Regulators are mechanical systems and the more you understand them, the less you'll fear them.

I'll dive my alpha as an octopus not primary for all testing purposes and I think that is a safe move.

I hope this thread is not going into "Should I service my own regs?"
I would appreciate information exchange and sharing of experience and knowledge for divers/non-divers who enjoy scuba in a different way.

It's 2010, lets go diving!

 

[fppf]

Oh, so its your buddy that will have the issue if there is one :shocked2:

I'm not turning this into a service your own regs thread.

What I am saying is do it right or don't do it at all, period. Wise man once said, you don't even know what you don't know. There are a lot of little things that can only be learned at a service clinic. There are also some special tools that are needed to do the job right.

Talk to your shop, if you only want to understand more they might let you sit and watch a rebuild. But from your questions it sounds like your on the edge about servicing regs, let alone picking substitute parts for them, which is not advised by manufactures for obvious reasons.

 

[AquaNSun]

Thanks fppf. I do have an air 2 as another octo just to clarify my reg set up so people dont get mistaken. I understand all inputs are well meant. Appreciated.

 

[redacted]

Awesome! I was looking at O-ring chart at oringusa.com and was wondering....

1. For Orifice and inlet coupling O-rings, would EPDM, 70-duro, be the appropriate choice for non-nitrox static applications in 2nd stages? The 70-duro, soft kind, was mentioned by oringusa as the standard and should be used whenever possible as the 90-duro might be too stiff? Would like to hear your experience.

2. It seems that most O-rings are classified under AS568 category, if that matters?

The nylon locknut is very small and I'll need to find another specialty store to confirm it's thread size. Been to regular hardware stores, like home depot, and all of them don't carry such small size. The closest size guessed so far is 4-40 thread. I read somewhere 5-40 thread so it's getting closed.

EPDM is appropriate for most scuba applications including use with recreational nitrox. Duro 70 is good for LP applications and some HP applications where extrusion is not a problem. Go with duro 90 for hp applications where extrusion may be an issue. There are a number of ASxxx categories (a lot like motor oil ratings: SA, SI...) and they don't seem to matter much for scuba as long as the size, material, and hardness are correct. Viton is another popular material (available in duro 75 and 90) but is more expensive than EPDM.

Mcmaster-Carr will probably have the nut if you can determine the thread size. I have found them for my Scubapro regs but I don't think I have ever changed a nyloc nut in about 10 years and have had no problem with reused ones holding adjustments.

It is not a bad idea to start out with kits but they will often not have all the o-rings you may need and they can be more expensive than individual parts. Most of the larger scuba manufacturers do not support the sale of parts to divers, yet you should be able to find sources if you work at it. Some countries do not allow manufacturers to withhold repair parts from users.

 

[Couv]

Edit: Awap was already in the middle of answering this, so please excuse the redundancy.

Hello AquaNSun,

Welcome to the Dark Side, ignore the naysayers and if you want to service your own equipment do so. As Awap will tell you diving gear is not life support equipment, but I'm going to steal a quote from someone else (Thalassmania, I think), "Yes, it is life support, that's why I service it myself."

I was just looking at the manual for the Oceanic Alpha 7, it's a good one. If you don't have one already, PM me with an email address where you can receive PDF files and I'll send one to you. Additionally, that looks like a good straight forward classic downstream dual adjustment second stage, if you really want to cheese off the "Don't Do it Yourself" crowd, get a home made poppet seat from Awap who punches them out of high quality EPDM. Speaking of quality, get quality o-rings from a reliable source, it is hit and miss at a hardware store.

Anyway, to answer you question, yes, for low pressure applications 70 duro EPDM or Viton is fine even with high concentrations of O2. Shore 90 for h.p. such as h.p hoses, tank neck to valves etc.

The nyloc nuts size is probably a 5-40 , but as mentioned, take the poppet to the hardware store and get the correct size. Having said that, get a stainless steel or brass nut to avoid problems with corrosion.

Here is the start of a wish list if you want to order from McMaster-Carr:
http://www.mcmaster.com/#

Part Number: 91831A006 1 Pack 18-8 Stainless Steel Nylon-insert Hex Locknut: 5-40 Thread Size*
Part Number: 91831A005 1Pack 18-8 Stainless Steel Nylon-Insert Hex Locknut 4-40 Thread Size (just in case)*
Part Number: 9557K462 100 -010 o-rings ($4.34 per Pack of 100*) (you will need more of these for l.p. ports and hoses) or
Part Number: 9561K11 25 -010 o-rings $3.00 per Pack of 25*
Part Number: 8297T121 100 -011 o-rings $9.00 per Pack of 100*
Part Number: 9557K441 80 - 906 $5.95 per Pack of 80 *

I'm sure you will find some other stuff there you might like such as stainless steel springs to make fin straps: Part Number: 3932K54 but you get the idea.

*Now I know this sounds like a lot of extra parts, so if you just need a few o-rings or 4-40 nuts (I do not currently have any 5-40) PM me and I'll get you started. But I warn you, once you start-there is no stopping.

Enjoy it,

Couv

 

[AquaNSun]

OMG the info provided is more than I expected! Awesome details!!!!!

My Alpha 7 has only 2 O-rings, one for Orifice and one for inlet coupling. As Im examining the unit, the coupling o-ring is used to seal out water, from external, and functions much like LP port plugs orings (static and low pressure application). The Orifice o-ring is also used to seal out water, from internal, (again same static and low pressure application). In my 2nd stage housing, and others, there are 3 holes/openings for air delivery to diver when poppet seat opens. These same holes will also allow water to enter the spring, poppet stem, and around orifice when the reg is out of diver's mouth. I think that's why you need an oring for the orifice and a total of 2. Just my observations with regard to O-rings and it's function in this case.

Thanks all, Im confident 70-duro will work for this application now.

....I am slowly getting to know awap, couv, da master, Luis, etc. by reading their threads....dark forces from the dark side great posts!